Heretofore, it was found possible to release the aforementioned locking systems without obtaining the correct combination under certain circumstances. One possibility was cranking the release knob without depressing any of the combination keys after the combinations on the tape were exhausted. Another possibility was to crank the release knob while depressing all the combination keys after the tape had been severed due to accident or damage. Either of these possibilities allowed the user to effect a release for the system while avoiding the proper unlocking procedure.
The present inventive improvement is designed to eliminate a releasing of the system when the reference combination fingers are either: (a) all depressed, or (b) all non-depressed.